1. Technical Field
The disclosure relates to a focused ion beam apparatus which performs working of a sample with a focused ion beam, a method of working a sample using the apparatus, and a computer program for focused ion beam working.
2. Description of Related Art
In the related art, a focused ion beam (FIB) apparatus has been used for performing etching working of a semiconductor device, for example, to obtain a cross section for observation, or for making a sample as a thin piece to manufacture a sample piece for a transmission electron microscope (refer to, for example, Japanese Patent No. 2973211). In addition, in recent years, it is also necessary to perform working of a sample into various shapes using the focused ion beam apparatus.
However, if the working time becomes longer, a stage or the like for placing a sample thereon during the working of the sample may drift or a beam may be deflected by charging of the sample, and accordingly a working location of the sample may be shifted. Herein, there is a known technology of previously registering a location of a location detection mark formed on the sample before the working and adjusting an emission location of an ion beam so as to correct the shift between a mark location during the working and the location of the location detection mark before the working (refer to, for example, JP-A-9-274879).
If the ion beam is emitted to the location detection mark several times during the working to detect the location thereof, the mark may be damaged by an ion sputtering phenomenon and accordingly, the mark may not be recognized. Herein, there is a known technology of forming a plurality of location detection marks on a sample, previously registering a location of each mark before the working, and sequentially switching the mark to be used in location correction during the working (refer to, for example, JP-A-2000-100360).